System and scheme on group based identity and scrambling for ue cooperation transmission

ABSTRACT

Systems and methods are provided to achieve data scrambling and transmission identification in the SL for UE cooperation (UC), in which one or more cooperating UEs help with a transmission to a target UE. Corresponding configuration schemes are also provided. In addition, systems and methods are provided to achieve data DMRS sequence generation and transmission identification in SL for UC, in which one or more cooperating UEs help with a transmission to a target UE. Corresponding configuration schemes are also provided. Furthermore, systems and methods of SL control channel scrambling and identification for UE cooperation are provided.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 62/864,823 filed Jun. 21, 2019, which is herebyincorporated by reference.

FIELD

The application relates to methods and apparatus for sidelinktransmission using scrambling sequences.

BACKGROUND

In current New Radio (NR) systems, transmission identification andscrambling are user equipment (UE) specific in support of UE datatransmission on the link between a gNodeB (gNB) and a UE, also referredto as the Uu link. Vehicle to everything (V2X) refers to a category ofcommunications scenarios (along with their corresponding technicalchallenges), including communication between a vehicle and anothervehicle (V2V), vehicle to infrastructure (V2I), vehicle to pedestrian(V2P), and many other scenarios. In V2X, the transmission can be donethrough a link between network and UE, such as uplink (UL) and downlink(DL), also referred to as Uu link, and using a sidelink between UE andUE (SL). UE cooperation can be used to enhance the reliability,throughput, and capacity of V2X communications, as well as nextgeneration wireless communications in general.

However, the existing approach of UE specific scrambling andtransmission identification is not appropriate for sidelinktransmissions, because for security reasons, it is undesirable to sharea UE identifier with most other UEs.

SUMMARY

Systems and methods are provided to achieve data scrambling andtransmission identification in the SL for UE cooperation (UC), in whichone or more cooperating UEs help with a transmission to a target UE.Corresponding configuration schemes are also provided. In addition,systems and methods are provided to achieve data DMRS sequencegeneration and transmission identification in SL for UC, in which one ormore cooperating UEs help with a transmission to a target UE.Corresponding configuration schemes are also provided. Furthermore,systems and methods of SL control channel scrambling and identificationfor UE cooperation are provided.

According to one aspect of the present disclosure, there is provided amethod in a UE comprising acting as a cooperating UE (CUE) to assist atleast one target UE (TUE) by: receiving a signal from a base stationcarrying a first modulated scrambled data block; demodulating,de-scrambling and decoding the first modulated scrambled data block toproduce a decoded data block; determining that the decoded data block isfor said at least one TUE; encoding the decoded data block to produce anencoded data block, and scrambling the encoded data block based on atleast a group ID to produce a scrambled data block; modulating thescrambled data block to produce a second modulated scrambled data block;transmitting the second modulated scrambled data block for reception bythe at least one TUE.

Optionally, the group ID is known by the UE and the at least one targetUE (TUE).

Optionally, the group ID is a function of one or more of: UE cooperation(UC) group ID, TUE sub-group ID, TUE PHY identity, TUE medium accesscontrol (MAC) ID, TUE higher-layer ID, CUE sub-group ID, CUE PHYidentity, CUE MAC ID, CUE higher-layer ID, cell ID.

Optionally, one or more of the following parameters is (or are)predefined, semi-statically configured by higher layer signaling, ordynamically configured by PHY layer signaling: UE cooperation (UC) groupID, TUE sub-group ID, TUE PHY identity, TUE medium access control (MAC)ID, TUE higher-layer ID, CUE sub-group ID, CUE PHY identity, CUE MAC ID,CUE higher-layer ID, cell ID.

Optionally, the transmitting is a unicast transmission to one TUE,wherein the one TUE is indicated or identified by a TUE sub-group ID ora combination of a UE cooperation (UC) group ID and the TUE sub-groupID.

Optionally, the transmitting is a unicast transmission to one TUE,wherein the one TUE is indicated or identified by a DMRS sequence.

Optionally, the DMRS sequence is generated based on at least a group IDassociated with the unicast transmission.

Optionally, the scrambling is also based on a group based datascrambling ID.

Optionally, the group based scrambling ID is: based on a configurationof the group based data scrambling ID received via higher layersignalling; or based on a cell ID.

In some embodiments, the method further comprises: for unicasttransmission to a single TUE, the group ID comprises a UE cooperationgroup ID (UC group ID) common to all members of a UC group combined witha TUE sub-group ID; for multicast transmission to a group of TUEs, thegroup ID comprises a UE cooperation group ID (UC group ID) common to allmembers of a UC group.

In some embodiments, the method further comprises: receiving signalingto configure the UE to assist the at least one TUE.

Optionally, the method further involves transmitting sidelink controlinformation (SCI) signaling indicating transmission resources andparameters for use by the at least one TUE in detecting and decodingsecond modulated scrambled data block.

Optionally, transmitting SCI signaling is performed using a group-casttransmission to one or more UEs in a group of UEs identified by thegroup ID or a unicast transmission to one TUE.

Optionally, transmitting sidelink control information (SCI) signalingfurther comprises:

scrambling a CRC of a set of sidelink control information (SCI)information bits based on at least the group ID, the SCI informationbits and the scrambled CRC together forming an SCI coded block;

scrambling the SCI coded block based on at least the group ID to producea scrambled SCI coded block;

modulating the scrambled SCI coded block to produce a modulated SCIcoded block;

transmitting the modulated SCI coded block for reception by the at leastone TUE;

wherein the group ID is known by the CUE and the at least one target UE(TUE).

Optionally, determining that the decoded data block is for said at leastone TUE comprises attempting to descramble the scrambled data block witha scrambling sequence specific to the CUE, and also with the scramblingsequence based on the group ID.

Optionally, the first modulated scrambled data block is scrambled with adifferent scrambling sequence than the second modulated scrambled datablock.

Optionally, the first modulated scrambled data block is modulated with adifferent modulation and coding scheme than the second modulatedscrambled data block.

According to another aspect of the present disclosure, there is provideda method in a UE, or a method according to any preceding claim, themethod comprising acting as a cooperating UE (CUE) to assist at leastone target UE by: the UE receiving a first demodulation reference symbol(DMRS) from a base station; the UE determining that the first DMRS isassociated with a modulated scrambled data block transmitted by the basestation for reception by the at least one target UE; the UE generating aDMRS based at least a group ID; modulating the DMRS to produce amodulated DMRS; transmitting the modulated DMRS for reception by atleast one target UE; wherein the group ID is known by the UE and the atleast one target UE (TUE), and the group ID comprises: a UE cooperationgroup ID (UC group ID) common to all members of a UC group; or UCsub-group ID specific to the target UE; or a UC group ID common to allmembers of a UC group and UC sub-group ID specific to the target UE.

Optionally, the UE is the only UE configured to assist the at least onetarget UE for the transmission, and wherein the group ID comprises: a UEcooperation group ID (UC group ID) common to all members of a UC.

Optionally, the UE is one of multiple UEs configured to assist the atleast one target UE for the transmission, and wherein the group IDcomprises: a group based ID combined with a CUE sub-group ID of the UE.

Optionally, the scrambling is also based on a group based datascrambling ID.

According to another aspect of the present disclosure, there is provideda method in a UE, or a method according to any preceding claim, themethod comprising acting as a cooperating UE (CUE) to assist at leastone target UE (TUE) by: the UE scrambling a CRC of a set of sidelinkcontrol information (SCI) information bits based on at least a group ID,the SCI information bits and the scrambled CRC together forming an SCIcoded block; the UE scrambling the SCI coded block based on at least agroup ID to produce a scrambled SCI coded block; modulating thescrambled SCI coded block to produce a modulated SCI coded block;transmitting the modulated SCI coded block for reception by the at leastone TUE; wherein the group ID is known by the UE and the at least onetarget UE (TUE).

Optionally, the group ID comprises: a UE cooperation group ID (UC groupID) common to all members of a UC group; or UC sub-group ID specific tothe target UE; or a UC group ID common to all members of a UC group andUC sub-group ID specific to the target UE; or cell ID; or cell IDcombined with one or both of UC group ID and UC sub-group ID.

Optionally, for unicast transmission to a single TUE, the group IDcomprises: a UE cooperation group ID (UC group ID) common to all membersof a UC group combined with a TUE sub-group ID.

Optionally, for multicast or group-cast transmission to a group of TUEs,the group ID comprises: a UE cooperation group ID (UC group ID) commonto all members of a UC group.

Optionally, the scrambling is also based on a group based controlscrambling ID.

Optionally, the group based control scrambling ID is based on aconfiguration of the group based control scrambling ID received viahigher layer signaling.

According to another aspect of the present disclosure, there is provideda method in a UE, or a method summarized above or described herein, themethod comprising acting as a cooperating UE (CUE) to assist at leastone source UE (SUE).

Optionally, the method involves the UE assisting at least one source UE(SUE), by receiving traffic from the at least one SUE and forwarding thetraffic to the base station or another UE.

Optionally, the UE is one of a group of more than one CUE in a UE groupthat are assisting the at least one target UE (TUE), wherein the UEgroup is associated with the group ID.

According to another aspect of the present disclosure, there is provideda method in a UE comprising acting as a target UE (TUE) by receiving atransmission of a data block and/or DMRS and/or SCI from at least oneCUE generated in accordance with one of the methods summarized above ordescribed herein.

In some embodiments, the method further comprises: receiving atransmission from a base station; performing diversity combination basedon the transmission received from the base station and the transmissionfrom at least one CUE.

According to another aspect of the present disclosure, there is provideda user equipment (UE) comprising at least a processor and memory, the UEconfigured to perform one of the methods summarized above or describedherein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the disclosure will now be described with reference tothe attached drawings in which:

FIG. 1 is a block diagram illustrating an example of atelecommunications network according to one embodiment; and

FIG. 2 is a block diagram illustrating an example of a network servingtwo UEs;

FIG. 3 is a block diagram illustrating CUE behavior in helping forward aTUE packet;

FIG. 4 is a block diagram illustrating group based data scrambling(descrambling is with the reverse process);

FIG. 5 is a block diagram illustrating data scrambling for unicasttransmission (or reverse for descrambling process);

FIG. 6 is a block diagram illustrating data scrambling for groupcast (orreverse for descrambling process);

FIG. 7 is a block diagram illustrating DMRS generation for a SL datatransmission for UC;

FIG. 8 is a block diagram illustrating DMRS sequence generation whenonly one CUE is configured to help TUE(s);

FIG. 9 is a block diagram illustrating DMRS sequence generation whenmore than one CUE is configured to help TUE(s);

FIGS. 10A and 10B are block diagrams illustrating scrambling schemes forSCI CRC and its coded block;

FIGS. 11A and 11B are block diagrams illustrating a scrambling scheme onSCI CRC and coded block for unicast;

FIGS. 12A and 12B are block diagrams illustrating a scrambling scheme onSCI CRC and coded block for group/broadcast;

FIG. 13A is a block diagram illustrating DMRS sequence generation for asidelink SUE data transmission; and

FIG. 13B is a block diagram illustrating sidelink SUE data scrambling.

DETAILED DESCRIPTION

In V2X, a packet will be transmitted from one UE to another UE withresources and parameters that are either pre-configured or dynamicallyindicated. The packet transmission can be unicast or group-cast.

To make the UE cooperation (UC) operational, UEs in common vicinity forma UE cooperation group. UE cooperation will involve both transmissionsbetween gNB and UEs (Uu link) and Sidelink (SL) transmissions betweenUEs.

For UE cooperation in NR, for example in DL transmission, the basestation can transmit a packet to a target UE (TUE) with the help of oneor more other UEs (referred to as cooperative UEs, or CUEs) in scenariossuch as the TUE having poor channel conditions or a poor geographiclocation. For a DL packet transmission in the Uu link, the packet dataand demodulation reference signal (DMRS) transmission is (or are)scrambled. If one or more CUE is able to help forward the packet datatransmission to the TUE by making a SL transmission, this will involveeach helping CUE receiving the packet data and DMRS, descrambling andre-scrambling (e.g., each by a different scrambling ID), andretransmitting (i.e., forwarding). The SL transmission includes UEidentification and transmission identification.

With UE cooperation, multiple CUEs may forward or relay traffic to orfrom one or more TUEs, with the result that there are redundant versionsignal transmissions that can be combined upon reception. To make itpossible for the redundant version signal transmissions to be combinedor detected more efficiently, the redundant version signals in each UE(CUE or TUE) may be configured such that the redundant version signaltransmissions can be transmitted or received in a cooperative way. Eachredundant version transmission signal from each CUE (or TUE) and from adifferent transmission time interval is clearly defined. For a downwardUC transmission (gNB downward to target UE in a UC group), even if oneCUE from a group of cooperating UEs is not able to forward the trafficdue to failure to successfully detect the traffic transmitted towardsthe TUE(s), the redundant version signals from the other UEs in the UCgroup can still be efficiently and jointly detected at the TUE(s). Theredundant version signals from one or more UEs can be repeated once aNACK is received. Optionally, multiple repetitions of a packettransmission from one or more UEs may be configured. In this case, therepetition transmissions of the packet can be terminated by receipt ofan ACK, for example, to avoid unnecessary interference to the system andsave UE energy. In some embodiments, a packet can be delivered to itsintended destination (e.g., TUE or gNB) via multiple hops involvingmultiple CUEs, i.e. a CUE in a UE cooperation group may forward or relaytraffic to or from one or more other CUE(s) belonging to the group (oreven another UC group that is configured to allow assistance among thegroups) as part of the UC transmission process.

Towards this end, configuration and signaling mechanisms are needed tomake the UC operation smooth and effective. In the Uu link, the gNB willneed to configure UE grouping for a UE group, including a configurationof the transmission and receiving resources, redundant signal versionsand forwarding scheme for a UE in the UC group.

The UC group then performs groupcast/broadcast transmission of a TUE'spacket upon its arrival to the UC group. This can involve multiple CUEsreceiving/detecting a packet from the gNB (on respective Uu links). TheCUEs that correctly receive the packet or directly detect DMRS, and inparticular those that are configured as helping UEs, will forward/sendinformation on the packet to the associated TUE(s).

Each CUE may be configured with redundant version signals of the packet.This may be achieved by way of pre-configuration, semi-staticconfiguration, or dynamic configuration. The CUEs forward the redundantversion signals of the packet in dedicated resources or shared resourceswith the same or different HARQ process IDs, which are configured orindicated by way of pre-configuration, semi-static configuration, ordynamic configuration. Helping CUEs that are not able to correctlydecode a packet or detect DMRS in a transmit time interval (TTI) willnot forward anything.

A redundant signal version can be, for example, chase combining (CC),incremental redundancy (IR), one cyclic delay diversity (CDD) version orone Alamouti encoding version, whose encoding scheme is associated witha forwarding scheme, e.g., amplify and forward (AF), decode and forward(DF), compress and forward (CF), etc. The associated parameters may bepre-configured, semi-statically configured or dynamically configured,for example using sidelink control information (SCI).

The TUE(s) can receive/detect based on a received Uu signal (ifpossible), as well as the (possibly redundant version) signals fromCUE(s) for signaling combining and detection as applicable. Oncedetected, the TUE(S) may provide feedback to CUE(s)/gNB accordingly.

In UC SL for an upward (from a source UE (SUE) to gNB) transmission, oneor more SUEs can forward their packet(s) to one or more CUEs, and theCUE(s) will then forward the packets upward to the gNB.

To support UE cooperation in both Uu and SL links, systems and methodsare provided that involve one or more of:

scrambling or/and forwarding TUE data by a helping CUE in a UC group;

for a CUE, transmitting a packet to a TUE via unicast or groupcasttransmission in UC scenarios; and

for TUE reception, identifying one or more CUEs that are forwarding theTUE packet.

Corresponding systems and methods are provided in relation to DMRS andSCI transmission and reception.

The scrambling employed in these embodiments can achieve up to threepurposes:

-   -   a. Transmission identification: a transmission can be identified        by a specific scrambling sequence, and the receiver can        determine the scrambling sequence used to make the transmission        and make the corresponding identification.    -   b. Data randomization: a more random signal can be more        efficiently and reliably transmitted with interference        randomization in the system;    -   c. Obscuring potentially confidential UE-specific information:        there are situations where it may be desirable to treat a UE        identifier as confidential, at least as between a given UE and        other UEs. Of course, the network needs to know the UE ID. In        conventional UE to BS transmissions, there is no problem using        the UE ID as a basis for signal identification. However, in UC        scenarios, using the UE ID of the target UE would result in all        UEs in the UC group knowing the UE ID of the target UE. As such,        some embodiments provide for the use of a group ID; a group ID        is an ID that is known to the UC group and can be configured via        higher layer signaling, for example, but the group ID is not the        same as any specific UE ID in the UC group.

Sequences for data scrambling and DMRS are usually pseudo-randomsequences, which can be generated in various schemes depending on themotivations and objectives such as general scrambling, referencesignals, lower PAPR (peak to average power ratio), etc. As an example ofa general form of sequence that can be applied to data scrambling orDMRS, pseudo-random sequences can be defined by a length-31 Goldsequence. An output sequence c(n) of length M_(PN), where n=0, 1, . . ., M_(PN)−1, is defined by Eq. (1)

c(n)=(x ₁(n+N _(C))+x ₂(n+N _(C)))mod 2

x ₁(n+31)=(x ₁(n+3)+x ₁(n))mod 2

x ₂(n+31)=(x ₂(n+3)+x ₂(n+2)+x ₂(n+1)+x ₂(n))mod 2  (1)

where N_(C)=1600 and the first m-sequence x₁(n) is initialized withx₁(0)=1, x₁(n)=0, n=1, 2, . . . , 30. The initialization of the secondm-sequence, x₂(n), is denoted by c_(init)=Σ_(i=0) ³⁰x₂ (i)·2^(i) withthe value depending on the application of the sequence.

In the detailed examples below, sequences are employed for SL data orDMRS scrambling that are based on the above general example. However, itshould be understood that the embodiments are not limited to thespecific examples.

When there are multiple inputs to scrambling sequence generation, thesecan be combined in various ways. When equation 1 is applied to differentapplications or scenarios, each scenario may have different ways ofdetermining the initialization c_(init), examples of which will beprovided in the following paragraphs.

FIG. 1 is a block diagram illustrating an example of atelecommunications network 1400 according to one embodiment, forimplementing any one or combination of two or more of the methodsdescribed herein. The telecommunications network 1400 includes a corenetwork 1402 and an access network 1406. The access network 1406 servesa plurality of UEs 1404 a, 1404 b, 1404 c, 1404 d, 1404 e, 1404 f, 1404g, 1404 h, and 1404 i. The access network 1406 could be an EvolvedUniversal Terrestrial Access (E-UTRA) network. As another example, theaccess network 1406 could be a cloud radio access network (C-RAN). Theaccess network 1406 includes a plurality of BSs 1408 a, 1408 b, and 1408c. The BSs 1408 a-c each provides a respective wireless coverage area1410 a, 1410 b, and 1410 c. Each of the BSs 1408 a-c could beimplemented using a radio transceiver, one or more antennas, andassociated processing circuitry, such as antenna radio frequency (RF)circuitry, analog-to-digital/digital-to-analog converters, etc.

Although not illustrated, the BSs 1408 a-c are each connected to thecore network 1402, either directly or through one or more centralprocessing hubs, such as servers. The BSs 1408 a-c could serve as agateway between the wireline and wireless portion of the access network1406.

Each one of BSs 1408 a-c may instead be referred to as a basetransceiver station, a radio BS, a network node, a transmit node, atransmit point, a Node B, an eNode B, or a remote radio head (RRH),depending upon the implementation.

In operation, the plurality of UEs 1404 a-i access thetelecommunications network 1400 using the access network 1406 bywirelessly communicating with one or more of the BSs 1408 a-c.

UEs 1404 a-d are in close proximity to each other. The UEs 1404 a-d caneach wirelessly communicate with the BS 1408 a, and they can alsodirectly communicate with each other, as represented at 1416. Thecommunications represented at 1416 are direct communications between UEsthat do not go through an access network component, such as a BS. Asshown in FIG. 4, UE to UE communications 1416 are directly between theUEs 1404 a-d and are not routed through the BS 1408 a or any other partof the access network 1406. Communications 1416 may also be referred toas lateral communications. In embodiments disclosed herein, UE to UEcommunications use an SL channel and an SL air interface. On the otherhand, a communication between an access network component, such as BS1408 a, and a UE, as in communication 1414, is called an accesscommunication. An access communication occurs over an access channel,which can be a UL or DL channel, and an access communication uses aradio access communication interface, such as a wireless radio accessair interface. Access and SL air interfaces may use differenttransmission formats, such as different waveforms, different multipleaccess schemes, and/or different radio access technologies. Someexamples of radio access technologies that could be used by an accessair interface and/or an SL air interface are: Long Term Evolution (LTE),LTE License Assisted Access (LTE-LAA), Fifth Generation (5G) New Radio(NR), and Wi-Fi.

By using the SL communications 1416, the UEs 1404 a-d may be able toassist with wireless communications between the UEs 1404 a-d and the BS1408 a. As one example, if UE 1404 c fails to correctly decode a packetreceived from the BS 1408 a, but if UE 1404 d is able to receive andcorrectly decode the packet from the BS 1408 a, then UE 1404 d coulddirectly transmit the decoded packet to UE 1404 c using SLcommunications 1416. As another example, if UE 1404 c moves out ofwireless coverage area 1410 c, such that UE 1404 c can no longerwirelessly communicate with the BS 1408 a, then UE 1404 b could forwardmessages between the UE 1404 c and the BS 1408 a. As another example, UE1404 a and UE 1404 c could both receive a signal transmitted from the BS1408 a that carries a packet meant for UE 1404 c. UE 1404 a may thentransmit to UE 1404 c, via SL communications 1416, the signal asreceived by UE 1404 a. UE 1404 c may then use the information receivedfrom UE 1404 a to help decode the packet from the BS 1408 a. In theseexamples, capacity and/or coverage may be enhanced through theassistance of UEs 1404 a, 1404 b, and/or 1404 d. V2X communications asreferenced herein are an example of SL communications.

The UEs 1404 a-d form a UE group 1420. The access network 1406 couldassign a group identifier (ID) to the UE group 1420. The UE group ID mayallow the access network 1406 to address the UE group 1420 as a wholeand distinguish the UE group 1420 from other UE groups. The UE group IDmay also be used to broadcast information within the UE group, i.e.address all other UEs within the UE group 1420. The UE group 1420 mayform a logical or virtual device mesh in which the members of the UEgroup 1420 communicate amongst themselves using UE communications overan SL air interface, but the UE group 1420 as a whole acts as a singledistributed virtual transceiver with respect to the access network 1406.The UE group ID may be a group radio network temporary identifier(G-RNTI), for example.

When a particular UE in the UE group 1420 is being assisted or is to beassisted with wireless communication between that UE and the BS 1408 a,then that particular UE is referred to as the target UE. In the examplesabove, UE 1404 c is being assisted and takes on the role of the targetUE. The UEs in a UE group other than the TUE form a cooperationcandidate set, which is a set of UEs that may cooperate to help the TUE.In FIG. 1, UEs 1404 a, 1404 b, and 1404 d in the group 1420 form acooperation candidate set. The subset of UEs in a cooperation candidateset that actually assist the target UE form a cooperation active set.The cooperation active set may be dynamically selected to assist thetarget UE. The UEs in the cooperation active set are referred to ascooperating UEs (CUEs). In UE group 1420, UEs 1404 a, 1404 b, and 1404 dform the cooperation candidate set. If UEs 1404 a and 1404 b actuallyassist target UE 1404 c, then UEs 1404 a and 1404 b form the cooperationactive set and are the CUEs. As UEs 1404 a-d move around, some may leavethe UE group 1420 and/or other UEs may join the UE group 1420.Therefore, the cooperation candidate set may change over time. Moregenerally, the cooperation candidate can be updated as needed. The UEgroup 1420 may also be terminated by the network 1406, e.g., if thenetwork determines that there is no longer a need or opportunity for theUE group 1420 to provide assistance in wireless communication betweenthe BS 908 a and members of the UE group 1420.

There may be more than one UE group. For example, UEs 1404 e and 1404 fin FIG. 1 form another UE group 1422.

FIG. 2 is a block diagram illustrating an example of a network 1552serving two UEs 1554 a and 1554 b, according to one embodiment. Thenetwork 1552 may be the access network 1406 from FIG. 4, and the two UEs1554 a and 1554 b may be two of the four UEs 1404 a-d in FIG. 7, or theUEs 1554 a and 1554 b may be UEs 1404 e and 1404 f in FIG. 4. However,more generally this need not be the case, which is why differentreference numerals are used in FIG. 5.

The network 1552 includes a BS 1556 and a managing module 1558. Themanaging module 1558 instructs the BS 856 to perform actions. Themanaging module 858 is illustrated as physically separate from the BS1556 and coupled to the BS 1556 via a communication link 1560. Forexample, the managing module 1558 may be part of a server in the network1552. Alternatively, the managing module 1558 may be part of the BS1556.

The managing module 1558 includes a processor 1562, a memory 1564, and acommunication module 1566. The communication module 1566 is implementedby the processor 1562 when the processor 1562 accesses and executes aseries of instructions stored in the memory 1564, the instructionsdefining the actions of the communication module 1566. When theinstructions are executed, the communication module 1566 causes the BS1556 to perform the actions described herein so that the network 1552can establish, coordinate, instruct, and/or control a UE group.Alternatively, the communication module 1566 may be implemented usingdedicated circuitry, such as an application specific integrated circuit(ASIC) or a programmed field programmable gate array (FPGA).

The UE 1554 a includes a communication subsystem 1570 a, two antennas1572 a and 1574 a, a processor 1576 a, and a memory 1578 a. The UE 1554a also includes a communication module 1580 a. The communication module1580 a is implemented by the processor 1576 a when the processor 1576 aaccesses and executes a series of instructions stored in the memory 1578a, the instructions defining the actions of the communication module1580 a. When the instructions are executed, the communication module1580 a causes the UE 1554 a to perform the actions described herein inrelation to establishing and participating in a UE group. Alternatively,the module 1580 a may be implemented by dedicated circuitry, such as anASIC or an FPGA.

The communication subsystem 1570 a includes processing andtransmit/receive circuitry for sending messages from and receivingmessages at the UE 1554 a. Although one communication subsystem 1570 ais illustrated, the communication subsystem 1570 a may be multiplecommunication subsystems. Antenna 1572 a transmits wirelesscommunication signals to, and receives wireless communications signalsfrom, the BS 1556. Antenna 1574 a transmits SL communication signals to,and receives SL communication signals from, other UEs, including UE 1554b. In some implementations there may not be two separate antennas 1572 aand 1574 a. A single antenna may be used. Alternatively, there may beseveral antennas, but not separated into antennas dedicated only to SLcommunication and antennas dedicated only to communicating with the BS1556.

SL communications could be over Wi-Fi, in which case the antenna 1574 amay be a Wi-Fi antenna. Alternatively, the SL communications could beover Bluetooth™, in which case the antenna 1574 a may be a Bluetooth™antenna. SL communications could also or instead be over licensed orunlicensed spectrum.

The UE 1554 b includes the same components described above with respectto the UE 1554 a. That is, UE 1554 b includes communication subsystem1570 b, antennas 1572 b and 1574 b, processor 1576 b, memory 1578 b, andcommunication module 1580 b.

The UE 1554 a is designated as a target UE (TUE) and will therefore becalled TUE 1554 a. The UE 1554 b is a cooperating UE and will thereforebe called CUE 254 b. The CUE 1554 b may be able to assist with wirelesscommunications between the BS 1556 and TUE 1554 a if a UE group were tobe established that included TUE 1554 a and CUE 1554 b. Othercommunication scenarios are also contemplated, and could be applied in aV2X application.

UE 1554 a may be specifically chosen as the target UE by the network1552. Alternatively, the UE 1554 a may itself determine that it wants tobe a target UE and inform the network 1552 by sending a message to theBS 1556. Example reasons why UE 1554 a may choose or be selected by thenetwork 1552 to be a target UE include: low wireless channel qualitybetween the UE 1554 a and the BS 1556, many packets to be communicatedbetween the BS 1556 and the UE 1554 a, and/or the presence of acooperating UE that is a good candidate for helping with communicationsbetween the BS 1556 and the UE 1554 a.

UE 1554 a need not always stay a target UE. For example, UE 1554 a maylose its status as a target UE once there is no longer a need or desirefor assistance with wireless communications between UE 1554 a and the BS1556. UE 1554 a may assist another target UE at a later time that wasitself previously a cooperating UE. In general, a particular UE maysometimes be a target UE and other times may be a cooperating UEassisting another target UE. Also, sometimes a particular UE may be botha target UE receiving assistance from one or more cooperating UEs andalso a cooperating UE itself assisting another target UE. In theexamples below, the UE 1554 a acts only as a target UE, i.e., TUE 1554a, and the UE 1554 b is a cooperating UE to the TUE 1554 a, i.e., CUE1554 b.

FIGS. 1 and 2 illustrate systems in which embodiments could beimplemented. In some embodiments, a UE includes a processor, such as1576 a, 1576 b in FIG. 2, and a non-transitory computer readable storagemedium, such as 1578 a, 1578 b in FIG. 2, storing programming forexecution by the processor. A non-transitory computer readable storagemedium could also or instead be provided separately, as a computerprogram product.

Packet forwarding by a CUE will now be described with reference to FIG.3. For a CUE to help receive and forward a packet transmission to a TUE,the CUE detects the packet transmission and identifies the packet asbeing for the TUE before doing some processing if applicable and sendingthe packet to the TUE in accordance with a forwarding scheme. Thisinvolves the CUE detecting the DMRS and performing channel estimationbased on the DMRS at block 100. If a decode and forward (DF) scheme isimplemented (yes path block 102), then block 103 is performed, andotherwise block 112 is performed. Block 103 is a decode and forwardscheme, in which demodulation, descrambling and decoding is performed at104 whose output consists of data bits and the data CRC bits. In block106, a cyclic redundancy check (CRC) is performed, and if the CRC fails,this is reported and the method stops. Otherwise, if the CRC passes, theCUE has recovered the correct data bits; then the data bits and the CRCbits are encoded to produce a data coded block. The data coded block isthen rescrambled, and remodulated at 108 before transmitting theremodulated data signal at 109. The CUE also transmits a DMRS at 120along with the data transmission at 109 to a TUE in SL.

Note that in some embodiments, the modulation scheme used in 108 over SLcan be different than the modulation scheme used to transmit to the CUEover the Uu link. Because the CUE and TUE may be more favorablysituated, there may be more options for modulation.

The DMRS transmitted by the CUE in SL needs to be different than theDMRS transmitted by the network (i.e., Uu link), because the DMRS istransmitted together with the data, such that the receiver (e.g., aTUE)) is able to distinguish between the DMRS associated with anoriginal transmission of the data from the network, and the DMRSassociated with another transmission from a CUE.

The data scrambling performed by the CUE for the SL transmission can bethe same as or different than that performed by the network (for the Uulink), with the result that a TUE can receive multiple versions of thetransmission (from the network and/or one or more CUEs) all using thesame or different scrambling sequences for data, depending onconfigurations, e.g., unicast, groupcast, how many CUEs to help TUE(s),etc., to be detailed in the following.

Block 112 is a non-DF scheme for the packet forwarding. In someembodiments, this involves the CUE performing at least one ofdemodulation, sampling and compression steps at 114, and thenremodulating at 116, and transmitting the result at 118. Once again, theCUE transmits a DMRS at 120 (with the same design as 109 for the DFscheme 103) along with the remodulated data signals at 116. In otherembodiments, the block 112 is simply an amplify-and-forwarding (AF)scheme.

For SL transmission, embodiments are provided in which theidentification and scrambling on a packet transmission are based on oneor more of:

UE specific transmission resources;

UE group transmission resources;

UC group ID, TUE identity; and

CUE identity (or identities);

where UE identity (CUE identify for CUE, TUE identity for TUE) can be UERNTI, DMRS, sub-group ID in a UC group, a temporary ID for UEcooperation, UE MAC ID(s) in SL, and/or UE Layer 1 (PHY layer) ID(s) inSL, where one or more of these identities can be pre-configured,semi-statically or/and dynamically configured via higher-layer signalingor/and PHY layer signaling.

Data Forwarding Embodiments Group Based Data Scrambling for SLTransmission Based on Group ID+Group Based Data Scrambling ID

Referring now to FIG. 4, shown is a first approach to data scramblingfor SL transmission by a CUE. Note that FIG. 4, and other similarfigures described herein, can be viewed as a flowchart of a methodfeaturing method steps. In the case of FIG. 4, the method steps includescrambling 202 and modulation 204 steps. An input to the method is adata coded block 200. However, the figure (and other similar figuresdescribed herein) can alternatively be viewed as an apparatus, in whichcase the apparatus features a respective functional block correspondingto each method step. In the case of FIG. 4, this would include ascrambler (that performs the scrambling) and a modulator (that performsthe modulation). Separate method and apparatus figures are not providedin the interest of brevity. In addition, the description of theflowchart of FIG. 4 and other similar flowcharts starts with a datacoded block defined in 108 and simply uses “scrambling” or “modulation”terminology rather than “re-scrambling” or “remodulation”.

For the purpose of FIG. 4, the CUE has already received data from thenetwork over the Uu link, and has encoded the data (and its CRC bits)into a data coded block. The data coded block sequence is scrambled at202 by a scrambling sequence that is determined by a group ID 206 and/ora group based scrambling ID. The group ID is, for example, a UEcooperation group ID (UC group ID), UC subgroup ID (i.e., sub-indexassociated with a specific UE in a UC group), or a combination of these.A group based data scrambling ID can be a scrambling ID configured byhigher layer signaling, or can be a cell ID if not configured by thenetwork.

For a CUE decoding and forwarding case with group based data scramblingin SL, though not provided in FIG. 4, the CUE may need to performdemodulation on the received packet transmission from Uu link, anddescrambling and decoding in the same way as described in 104 and 106 ofFIG. 3. Once CRC is checked correctly, the CUE encodes the correctlyreceived information bits and the information CRC to yield the datacoded block. The data coded block is then scrambled and modulated asdescribed in FIG. 4. If the CRC check fails, the CUE may report theerror detection and/or act as instructed by configuration.

From the reception perspective, the TUE will demodulate and descramblethe received transmission from the CUE. The descrambling procedure is areverse process to FIG. 4. If more than one CUE is configured to forwarddata, the TUE will detect multiple diversity transmissions from multipleCUEs and combine the diversity transmissions for better detection ifapplicable.

For one codeword having index q (where q=0 or 1 is an index of two datastreams) (or data coded block), a starting point is a block of bitsb^((q))(0), . . . , b^((q))(M_(bit) ^((q))−1), where M_(bit) ^((q)) isthe number of bits in codeword q to be transmitted on the physicalchannel. These bits are scrambled prior to modulation, resulting in ablock of scrambled bits {tilde over (b)}^((q))(0), . . . , {tilde over(b)}(q)(M_(bit) ^((q))−1) according to

{tilde over (b)} ^((q))(i)=(b ^((q))(i)+c ^((q))(i))mod 2  (2)

where the scrambling sequence c^((q))(i) is given by Eq. (1) and q isselected from {0 or 1}. In a specific example, the scrambling sequencegenerator is initialized with

c _(init) =n _(RNTI)·2¹⁵ +q·2¹⁴ +n _(ID)  (3)

Where

n_(ID)∈{0, 1, . . . , 1023} is configured by the higher-layer signallingas a scrambling ID (or IDs), and n_(ID)=a group ID or N_(ID) ^(cell) ifnot configured; and

n_(RNTI) equals a group based ID, C-RNTI, MCS-C-RNTI, or CS-RNTI.

In the above:

A group based ID can be cell based, a group of cells based, or can bedecoupled with any cell;

RNTI is radio network temporary identifier;

C-RNTI is cell-RNTI;

MCS-C-RNTI is modulation and coding scheme RNTI;

CS-RNTI is configured scheduling RNTI.

Group Based Data Scrambling for Unicast Transmission Based on UC GroupID+TUE Sub-Group ID+Group Based Data Scrambling ID

Referring now to FIG. 5, shown is an approach to data scrambling forunicast transmission. The data coded block is scrambled at 202 by ascrambling sequence whose initialization is a function of UC group IDand TUE sub-group ID. Optionally, c_(init) is also a function of a groupbased data scrambling ID that may, for example be configured by higherlayer signaling (such as RRC) or by pre-configuration, for SL unicasttransmission. Note that if more than one CUE is configured to help theTUE, a configured diversity scheme can be applied for each CUE.

The scrambling sequence initialization is based on which is a functionof at least one of UC group ID, UE ID, sub-group ID(s), a group baseddata scrambling ID(s). In some embodiments, the formulation based on Eq.(3) is used. In this case the group ID in Eq. (3) can be replaced by afunction of at least one of UC group ID, UE ID(s), TUE sub-group ID, CUEsubgroup ID, SUE and cell ID.

From the reception perspective, the TUE will demodulate and descramblethe received transmission from the CUE. The demodulation anddescrambling procedure is a reverse process to FIG. 5 for CUEtransmission. If more than one CUE is configured to forward data, theTUE will detect multiple diversity transmissions from the CUEs andcombine the diversity transmissions for better detection if applicable.

The above transmission resources and parameters can be configured orindicated by RRC/SL-RRC or/and DCI/SCI.

Group Based Data Scrambling for Groupcast Transmission Based on UC GroupID+Group Based Data Scrambling ID

Referring now to FIG. 6, shown is an approach to data scrambling forgroupcast transmission. The data coded block is scrambled at 202 by ascrambling sequence that is a function of UC group ID. Optionally, thescrambling sequence is also a function of a group based data scramblingID configured by higher layer signaling (e.g., RRC) or bypre-configuration, for SL groupcast transmission. Note that if more thanone CUE is configured to help the TUE, a configured diversity scheme canbe applied for each CUE.

The scrambling sequence initialization is based on c_(init) which is afunction of at least one of UC group ID, UE ID(s), sub-group ID(s), agroup based data scrambling ID(s). In some embodiments, a formulationbased on Eq. (3) is used. Here, the more general a group ID in Eq. (3)is replaced by a function of at least one of UC group ID, UE ID(s) andcell ID.

From the reception perspective, the TUE will demodulate and descramblethe received transmission from the CUE. The descrambling procedure is areverse process to FIG. 6. If more than one CUE is configured to forwarddata, the TUE will detect multiple diversity transmissions from the CUEsand combine the diversity transmissions for better detection ifapplicable.

The above transmission resources and parameters can be configured orindicated by RRC/SL-RRC or/and DCI/SCI.

DMRS Embodiments

A demodulation reference symbol (DMRS) for data transmission is asequence transmitted by a UE in a pattern of resource elements (REs)within a location. For example, a 10 element sequence might betransmitted using 10 REs. These can be associated with a pattern thatdefines the 10 REs within a 10 OFDM symbol by 100 subcarrier resourcespace. The location specifies which 10×100 resource space to use.

For the data transmission in SL, DMRS configuration can be employed fortransmission identification and channel estimation for signaldemodulation. Referring to FIG. 7, shown is a DMRS generator/generatingstep 500, and a modulator/modulation step 502. An input to the DMRSgenerator/generation 500 is one or more of the following:

a group based ID 508 such as UC group ID, a sub-group ID, or acombination of them;one or more group based RS scrambling ID(s) 510 that can be configuredby one or more of RRC, SL-RRC, DCI and SCI signaling; or cell ID if notconfigured or by default.

The DMRS generator/generation 500 may also use an n_(SCID)defined/configured by one or more of RRC, SL-RRC, DCI and SCI signaling,or a predefined default value (e.g., 0).

A group ID and a group based scrambling ID(s) can be applied to generateDMRS for data transmission. In some embodiments, the UE uses a DMRSsequence r(n) defined by Eq. (4)

$\begin{matrix}{{r(n)} = {{\frac{1}{\sqrt{2}}\left( {1 - {2 \cdot {c\left( {2n} \right)}}} \right)} + {j\frac{1}{\sqrt{2}}{\left( {1 - {2 \cdot {c\left( {{2n} + 1} \right)}}} \right).}}}} & (4)\end{matrix}$

where the pseudo-random sequence c(i) is defined in Eq. (1). Thepseudo-random sequence generator is initialized based on c_(init)=afunction of at least one of a group ID, UE ID(s), sub-group ID(s), agroup based data scrambling ID(s), and n_(SCID). In some embodiments aformulation based on Eq. (5) given below is used

c _(init)=(2¹⁷(N _(symb) ^(slot) n _(s,f) ^(μ) +l+1)(2N _(ID) ^(n)^(SCID) +1)+2N _(ID) ^(n) ^(SCID) +n _(SCID))mod 2³¹  (5)

-   -   where l is the OFDM symbol number within the slot, n_(s,f) ^(μ)        is the slot number within a frame, and        -   N_(ID) ⁰, n_(ID) ¹∈{0, 1, . . . , 65535} are given by the            higher-layer parameters group based RS scramblingID0 and            group based RS scramblingID1, respectively, in higher-layer            signalling if provided. In this case, PDSCH is scheduled by            PDCCH with the DCI CRC scrambled by a group ID, C-RNTI,            MCS-C-RNTI, or CS-RNTI; or        -   N_(ID) ⁰∈{0, 1, . . . , 65535} is given by the higher-layer            parameter group based RS scramblingID0 in higher-layer            signaling if provided. In this case, the PDSCH is scheduled            by PDCCH with the DCI CRC scrambled by a group ID, C-RNTI,            MCS-C-RNTI, or CS-RNTI; or        -   N_(ID) ^(n) ^(SCID) =a Group ID or N_(ID) ^(cell) otherwise;        -   The quantity n_(SCID)∈{0, 1} may be specified given by a            DMRS sequence initialization field, in the DCI associated            with the PDSCH transmission, otherwise n_(SCID)=0.            DMRS Sequence Generation when Only One CUE is Configured to            Help TUE(s)

Referring now to FIG. 8, shown is an embodiment where only one CUE isconfigured to help TUE(s), and the DMRS sequence generation 610 isassociated with the UC group ID 608 or/and a configured group based RSscrambling ID(s) 610 for either unicast or groupcast data transmissionfrom the CUE. These configurations can be done by one or more of RRC,SL-RRC, DCI and SCI signaling. In this configuration, the single CUEacts as a UE relay, with a special characteristic to scramble theforward traffic (in the SL). The CUE may relay or forward a (scrambled)packet to a TUE (or UEs) in a UE cooperation group. For SL unicasttransmission in UC, the UC group based ID in FIG. 8 can be replaced bythe TUE sub-group ID, the CUE sub-group ID or a combination of UC groupID with either of the TUE sub-group ID and the CUE sub-group ID.Alternatively or furthermore, the DMRS sequence generation in FIGS. 7˜9may involve antenna port and/or beamforming configurations in terms of aUE group based, UC group based, TUE based or/and CUE based antenna portand beamforming parameters. In some embodiments, both unicast andgroupcast are supported. Which of the two transmission types (unicast orgroupcast) is to be performed in SL can be configured or indicated byRRC/SL-RRC or DCI/SCI.

The pseudo-random sequence generator is initialized based on c_(init)=afunction of at least one of UC group ID, UE ID(s), sub-group ID(s), agroup based data scrambling ID(s), and n_(SCID). In some embodiments, aformulation based on Eq. (5) is used where a group ID can be a UC groupID, a TUE/SUE ID, a CUE ID, a sub-group ID, or a combination of them.

For a TUE reception on DMRS detection, the TUE may use the UC group IDor/and a configured group based RS scrambling ID(s) as described in FIG.8 to detect DMRS. If DMRS is detected correctly, the TUE will performdata demodulation and descrambling following the data proceduredescribed in the previous paragraphs. For groupcast such as in FIG. 8,all TUE(s) in the UC group will need to detect the CUE DMRS and thenfollow the demodulation and descrambling procedure.

DMRS Sequence Generation when More than One CUE is Configured to HelpTUE(s)

In other embodiments where more than one CUE is configured to helpTUE(s), the DMRS sequence generation is associated with one or more ofUC group ID, CUE sub-group ID, TUE sub-group ID 708 and configured groupbased RS scrambling ID(s) 710 for either unicast or groupcast datatransmissions from more than one CUE, as shown in FIG. 9. Two or moreCUEs apply a certain (joint) transmission scheme such as Alamoutiencoding or diversity encoding that can be configured. Theseconfigurations can be done by one or more of RRC, SL-RRC, DCI and SCIsignaling.

The pseudo-random sequence generator is initialized with a function ofc_(init)=a function of at least one of UC group ID, UE ID(s), sub-groupID(s), a group based data scrambling ID(s), and n_(SCID). In someembodiments, a based on Eq. (5) is used where the group ID can be a UCgroup ID, a TUE/SUE ID, a CUE ID, a sub-group ID, or a combination ofthem. The objective is for a TUE/SUE to be able to detect the helpingtransmission sources from the multiple CUEs for appropriate signalcombining or joint detection. The design on DMRSs for data transmissionsof two or more CUEs can be considered from two perspectives: 1) theDMRSs in the data transmissions are different from CUEs and thus areidentifiable in terms of transmission UE(s) at the receiver end; 2) theDMRSs in the data transmissions can have the same or different forms,and refer to the reception UE. As a result, DMRSs from multipletransmission ends can be associated with UC group ID, UE IDs, subgroupID(s) for TUE/SUE, subgroup ID(s) for CUEs, time-frequency resourceallocations, etc., as long as the DMRS formations can be unique in termsof a combination of these associations. For example, two CUEs may use asingle/same DMRS to forward the data packets in identifiabletime-frequency resources where the DMRS can be designed based on TUE IDsor UC group ID with TUE sub-group ID; or can use CUEs' individual (anddifferent) DMRSs to transmit the data in same time-frequency resources(and possibly with different transmission redundant/diversity versionsthat are configured). The CUEs' individual (and different) DMRSs can bedesigned based on their individual IDs or optionally to be designedbased on UC group ID with individual CUE subgroup ID.

For a TUE to perform DMRS detection, the TUE differentiates thetransmissions from more than one CUE. A TUE may use the samedefined/configured IDs used for DMRS generation as described in FIG. 9to detect DMRS(s) for data transmission(s) from the CUE(s). If more thanone data transmission is received, the TUE may detect and combine thetransmissions from different CUEs according to a configured transmissionscheme. These configurations can be done by one or more of RRC, SL-RRC,DCI and SCI signaling.

SL Control Information (SCI) Embodiments

The SL control information (SCI) carries scheduling and configurationfor a SL data transmission, including at least one of time-frequencyresources, data scrambling sequence(s), DMRS configuration(s),Modulation and coding scheme (MCS), group ID, CUE identification, TUEidentification, CUE forwarding scheme, beamforming parameters, HARQconfiguration, etc.

In some embodiments, a CRC is computed based on SCI information bits,and the CRC is scrambled at 804 by a group ID as shown in FIG. 10A. Theoverall SCI includes SCI information bits, and the CRC parity bits.After attachment, the CRC parity bits are scrambled with a group or UEID, x_(rnti,0), x_(rnti,1), . . . , x_(rnti,15), where x_(rnti,0)corresponds to the MSB of the RNTI (i.e., the group ID or UE specific IDhere), to form the sequence of bits c₀, c₁, c₂, c₃, . . . , c_(K-1). Therelation between c_(k) and b_(k) is:

c_(k)=b_(k) for k=0, 1, 2, . . . , A+7, and

c _(k)=(b _(k) +x _(rnti,k-A-8))mod 2 for k=A+8,A+9,A+10, . . .,A+23,  (6)

where K=A+L, A is the payload size and L is the number of parity bits.The group ID can be a function of at least one of UC group ID, UCsub-group ID (CUE or/and TUE), a Cell ID, or a combination of them. SCIwill be used to support both unicast and groupcast (or broadcast). SCImay or may not indicate/configure a resource and transmission parameterpool for a group of UEs in UC. After the CRC scrambling, the informationbits and the scrambled CRC are encoded to produce a SCI coded block, andthe SCI coded block is subject to further scrambling as shown in FIG.10B.

As shown in FIG. 10B, an SCI coded block 850 is scrambled 852 by afunction of at least of one of a group ID 856 and a group based controlscrambling ID 858. A group ID can be can be a function of at least oneof UC group ID, UC sub-group ID (TUE or/and CUE). A group based controlscrambling ID can be a configured scrambling ID for its DMRS by higherlayer signaling, which, for example, can be a group ID, or cell ID bydefault or if not configured by the network. Following scrambling at858, the scrambled SCI is modulated at 854, and then transmitted withDMRS used for SCI transmission.

For SCI coded block scrambling, a group ID or/and a group based controlscrambling ID can be used. For example, the UE has a block of bits b(0),. . . , b(M_(bit)−1) to transmit, where M_(bit) is the number of bitstransmitted on the physical channel, these bits are scrambled prior tomodulation, resulting in a block of scrambled bits {tilde over (b)}(0),. . . , {tilde over (b)}(M_(bit)−1) according to

{tilde over (b)}(i)=(b(i)+c(i))mod 2

where the scrambling sequence c(i) is given by Eq. (1). The scramblingsequence generator is initialized with

c _(init)=(n _(RNTI)·2¹⁶ +n _(ID))mod 2³¹  (7)

where

-   -   for a UE-specific search space, n_(ID)∈{0, 1, . . . , 65535}        equals the higher-layer parameter value of group based        scrambling ID (or a UE specific scrambling) if configured,    -   n_(ID)=N_(ID) ^(cell) otherwise        and where    -   n_(RNTI) is given by the group ID, the C-RNTI for a PDCCH in a        UE-specific search space if the higher-layer parameter, group        based scrambling ID (or a UE specific scrambling ID is        configured, and    -   n_(RNTI)=0 otherwise.

In some embodiments, DMRS for SCI transmission is generated based on agroup ID (as described above) or/and a configured ID for a UC group.

SL Control Information (SCI) for Unicast

In a specific example, for unicast transmission, the SCI CRC isscrambled using a group ID that is a function of the UC group ID and TUEsub-group ID (or index in the group) as shown in FIG. 11A. Followingthis, SCI coded block scrambling is performed as shown in FIG. 11B,using the same function used for the SCI CRC, and optionally a groupbased control scrambling ID is configured by higher-layer signaling,e.g., RRC/SL-RRC. Alternatively or furthermore, the group ID is afunction of one or more of UC group ID, TUE sub-group ID, TUE PHYidentity, TUE MAC ID, TUE higher-layer ID, CUE sub-group ID, CUE PHYidentity, CUE MAC ID, CUE higher-layer ID, and cell ID that arepre-configured or configured by higher-layer signaling or PHY layersignaling; such defined group ID may also be applicable to associatedFigures described previously (e.g., FIGS. 5 and 9) and after (e.g.,FIGS. 11A and 11B).

For SCI coded block scrambling for unicast, UC group ID, UE ID or/andTUE sub-group ID can be used for CRC scrambling using a formulationbased on equation (6). The UE SCI coded block can be applied with aformulation based on equation (7), where n_(RNTI) is given by UC groupID, UE ID, TUE subgroup ID, CUE subgroup ID or/and a group basedscrambling ID (or a UE specific scrambling ID). DMRS generation may bebased on a group ID (e.g., n_(RNTI)) and/or group based RS scramblingID.

Receiving UE (TUE) behavior for this case involves all of the TUEs inthe UC group detecting the SCI. Following that, the TUE that is intendedfor reception will receive the forwarded data from the CUE(s). Based onconfigured UC operation mode (e.g., only one CUE or more than one CUE toforward data), the TUE will receive the forwarded data accordingly asdescribed previously.

SL Control Information (SCI) for Group/Broadcast

In a specific example, for group/broadcast transmission, thetransmission UE (CUE) scrambles the CRC with a UC group ID, as depictedin FIG. 12A. SCI coded block scrambling is performed as depicted in FIG.12B, using a function of at least one of the UC group ID, a group basedcontrol scrambling configured by higher layer signaling, e.g.,RRC/PCS-RRC.

For SCI coded block scrambling for groupcast/broadcast, UC group ID,cell ID, UE ID or/and TUE sub-group ID can be used for CRC scramblingusing a formulation based on equation (6). The UE SCI coded block can beapplied with a formulation based on equation (7), where n_(RNTI) isgiven by UC group ID, cell ID, UE ID, TUE subgroup ID, CUE subgroup IDor/and a group based scrambling ID (or a UE specific scrambling ID).DMRS generation may be based on a group ID (e.g., n_(RNTI)) and/or groupbased RS scrambling ID.

SCI will be sent to the UE group via a control channel resourceconfigured by higher layer signaling, e.g., RRC/PCS-RRC, pre-configuredor pre-defined.

Receiving UE (TUE) behavior for this case involves all the TUEs in theUC group detecting the SCI in order to obtain transmission parameters,for example a resource allocation for data. Based on configured UCoperation mode (e.g., only one CUE or more than one CUE to forwarddata), the TUE(s) will receive the forwarded data accordingly asdescribed previously.

Transmissions from Source UE to Base Station Via CUE

The above embodiments have focused on transmission from a base stationto a TUE via one or more CUEs. For a UE cooperative transmission from aSUE to the base station via a CUE, i.e., SL and uplink transmission, theSUE in a UC may generate DMRS as shown in FIG. 13A and perform datascrambling in SL as shown in FIG. 13B.

As shown in FIG. 13A, SUE DMRS generation uses a group based ID(s). Thepseudo-random sequence generator for SUE DMRS is initialized based onc_(init)=a function of at least one of UC group ID, UE ID(s), sub-groupID(s), a group based data scrambling ID(s), and n_(SCID). In someembodiments, the formulation in Eq. (5) is used where group ID can be aUC group ID, a TUE/SUE ID, a CUE ID, a sub-group ID, or a combination ofthem. For DMRS, in some embodiments, the SUE transmits the SUE's DMRSconfigured by either semi-statistic (e.g., higher-layer, RRC signaling)or dynamic signaling (e.g., DCI/SCI).

This can, for example, be a function of at least one of the UC group ID,SUE subgroup ID. DMRS generation may also be based on a configured groupbased RS scrambling ID.

As shown in FIG. 13B, SUE data scrambling may be based on a group IDthat may be a function of at least one of UC group ID, SUE sub-group ID,and a group based data scrambling ID configured by higher layersignaling, semi-static or dynamic configuration to support eitherunicast or groupcast.

For data coded block scrambling, for example, the scrambling sequenceinitialization is based on c_(init)=a function of at least one of UCgroup ID, UE ID, sub-group ID(s), a group based data scrambling ID(s).One embodiment is to use formulation in Eq. (3), where in this case agroup ID can be replaced by a function of at least one of UC group ID,UE ID(s), SUE sub-group ID, CUE subgroup ID, SUE and cell ID.

CUE Behavior for Transmissions from Source UE to Base Station Via CUE

One or more CUEs can be configured to help the SUE. One or more CUEsdetect SUE DMRS (as known to the CUEs). One or more CUEs will performdata demodulation, and descrambling using reverse procedure described inFIGS. 13A and 13B, and if the decoded bits pass CRC check, these bitswill be re-encoded, re-scrambling and re-modulated before forwarding tothe base station. The re-scrambling for Uu link can have the same ordifferent scrambling sequence from SL.

CUE with Knowledge of Specific UE Information Including Scrambling IDs

The above embodiments have focused on the use of various group basedIDs, and group based scrambling IDs for DMRS, data and SCI transmission.More generally, for UE cooperation or relaying in a UC group, as long asa CUE has knowledge of specific UE transmission and parameterinformation such as the UE ID(s), its (their) corresponding scramblingID(s), UE transmission state (e.g., RRC connected, or RRC idle, etc.),and/or DRX cycle in SL/Uu link, etc., on one or more TUEs (or SUEs), theCUE is able to either forward downward the transmissions of the packetsto the TUE(s) from the base station or forward upward the transmissionsof part or entire packets from the SUE(s) to the base station, given thepre-configured (by, e.g., higher-layer signaling) or/and dynamicallyconfigured (by, e.g., L1 signaling) cooperation relationship betweenCUE(s) and TUE(s)/SUE(s).

A CUE can be configured or defined as to provide an operational functionof either bidirectional (i.e., forwarding both DL and UL traffic in SL)or unidirectional (i.e., forwarding either UL or DL traffic in SL).Moreover, the two operational functions from a CUE may be different. Forexample, the resource configuration or allocation for UC in a SLtransmission with CUE bidirectional operation can be similar to the basestation's, e.g., using control information to allocate the transmissionresources and parameters (i.e., SCI in SL link to take a similarfunctionality of DCI in Uu link). A CUE with unidirectional operationmay not able to operate in such a manner. However, the resourceconfiguration or allocation should be the same for bidirectional andunidirectional operations in terms of a CUE (and a base station)requiring transmission & parameter information to send any packet fromthe base station to a TUE or receive any packet from a SUE toforward/relay to the base station.

In some embodiments, the members within a UC group can share sometemporary IDs such as the above referenced UE ID such as RNTI and the UEscrambling ID(s) for UE data scrambling/identification and transmissionsin a SL or a Uu link; for example, a family of members, members ordevices in a factory or corporation, a group of validated orsecurity-checked members, or a dynamically/temporarily formed group forpublic events or rescue, etc., can share their mutual IDs necessary fordata transmissions. This shared information can be exchanged betweenCUE(s) and TUE(s)/SUE(s), pre-configured semi-statically by high-layersignaling, or configured dynamically by DCI or SCI. As a result, insteadof a group ID for a UC group, at least a CUE with a helping relationshipwith a TUE/SUE can have the TUE/SUE ID and its specific scrambling ID(s)if needed. Thus, in a Uu link transmission, the TUE/SUE ID such as RNTIcan be used to scramble DCI CRC in the PDDCH channel, such that thehelping CUE can detect the traffic from the DCI for and then forwardtowards the TUE/SUE.

In above embodiments, the CUE detects a DCI message (e.g., schedulinginformation) from a Uu link multiple times, one detection attempt basedon its own ID (to check if any traffic to itself, if not) and the otherdetection attempt(s) based on the ID(s) of its helping TUE(s)/SUE(s) (inone or more UC groups to check if any helping traffic to arrive).

In other embodiments, given a CUE having a TUE/SUE ID and/or itsscrambling ID(s) with a configured/defined UC relationship among them,the transmission data/message (e.g., in PDSCH channel) to the TUE/SUEcan be scrambled by the TUE/SUE ID or/and its scrambling ID(s). The DCICRC can be scrambled by the CUE ID (such as its RNTI) such that the CUEcan detect the DCI to get some information of traffic to it. Thedata/message descrambling process will require detecting based on one ormultiple UE IDs and scrambling IDs, one for its own ID or/and its ownscrambling ID(s), and (if not for its own) the other(s) trying theTUE/SUE ID(s) or/and its (their) scrambling ID(s), in order to figureout if the traffic is for itself or others (in one or more UC groups).

It is noted that as one operational option, it is possible that when aCUE is helping receive a data or control message transmission from thebase station toward a TUE/SUE, and then forwarding a transmission of thedata or control message to the TUE/SUE, the TUE/SUE can also receive thedata or control transmission from the base station at the same time,which can be optionally combined with the transmission from the CUE forsignal detection and decoding as needed.

CUE Selection

To be a CUE, a UE should have a reasonably good channel condition(unless all the nearby UEs are in poor channel conditions) in its Uulink. However, a UE that is very close to the base station may not be anideal candidate as a CUE, especially from the perspective of ULinterference incurrence for a location very close to the base station.

As a CUE in a UC group, the CUE can help forward or relay a packettowards a TUE or a packet from SUE in the UC. The CUE has its own datatransmission requirement in the Uu link. A UE with carrier aggregation(CA) or dual connectivity (DC) links with one or more base stations canbe an ideal candidate as a CUE. At least one of the CA or DC links canbe configured for UC.

Given the scrambled data/message transmission for a UE in Uu (or SL)link, the transmission should be performed in a traffic or controlchannel, thus the UE has knowledge of the traffic channel or controlchannel, whose time and frequency resources can be configuredsemi-statically or dynamically, for example, using high-layer signalingor DCI signaling. For UE cooperation, the time-frequency resourcesand/or transmissions parameters for DL and/or UL can be pre-configuredsemi-statically, e.g., via high-layer signaling, or configureddynamically, e.g., via, L1 signaling, for Uu and/or SL. In someembodiments, the resource/parameter configurations between Uu and SLlinks can be mapped for UC, which means that the resource/parameterconfiguration in Uu link has a pre-configured or pre-definedrelationship with the resource/parameter configuration in SL link (andverse versa for SL configuration to Uu configuration), thus making bothCUE(s) and TUE(s)/SUE(s) (in one more UC groups) more readily used forCUE data reception, CUE forwarding/relaying, TUE data reception or SUEdata transmission.

In one embodiment, the pre-configured (e.g., by RRC or/and DCI)time-frequency resources in SL and Uu links (optionally with a mappingrelationship between SL and Uu links) for one or more UC groups cansupport a grant-free transmission. In UL, a SUE may choose one or moreconfigured resources in SL link for a data transmission to a CUE (ormore CUEs) that may forward/relay data transmission (with a possibleprocessing such as de-scrambling and re-scrambling, or re-do MCS, beforesending out) to the base station in the configured resources in Uu link;similarly in DL, a CUE (or more CUEs) may receive a data/messagetransmission in the Uu link (resources) and forward to a TUE or SUE inthe SL link (resources).

Given above descriptions on data/control scrambling and transmissionidentification for UE cooperation where both Uu and SL are involved, theabove proposed data/control scrambling and transmission identificationschemes can be directly applied to SL only scenario, where a UE ID canbe any SL UE ID such as SL Layer 1 source or destination ID(s), SL MAClayer ID(s), RNTI, and/or SL based group ID, etc. In the SL onlyscenario, a CUE is simply a transmission UE and a TUE is reception UE inSL.

It should be understood that the above methods can be combined. Forexample, another embodiment includes the data forwarding and DMRSforwarding. Another embodiment includes data forwarding and SCI. Anotherembodiment includes data forwarding, DMRS forwarding, and SCI.Corresponding embodiments relate to UE functionality for receiving thedescribed CUE transmissions.

Corresponding embodiments relate to transmission from a SUE to one ormore CUEs, and to transmission from one or more CUEs to a base stationto forward data, DMRS from an SUE. The options for scrambling describedabove, for application for CUE to TUE transmission, apply to SUE to CUEtransmission. The options for scrambling described above for basestation to CUE transmission apply to CUE to base station transmission.

Numerous modifications and variations of the present disclosure arepossible in light of the above teachings. It is therefore to beunderstood that within the scope of the appended claims, the disclosuremay be practiced otherwise than as specifically described herein.

1. A method in a UE comprising acting as a cooperating UE (CUE) toassist at least one target UE (TUE) by: receiving a signal from a basestation carrying a first modulated scrambled data block; demodulating,de-scrambling and decoding the first modulated scrambled data block toproduce a decoded data block; determining that the decoded data block isfor said at least one TUE; encoding the decoded data block to produce anencoded data block, and scrambling the encoded data block based on atleast a group identifier (ID) to produce a scrambled data block;modulating the scrambled data block to produce a second modulatedscrambled data block; transmitting the second modulated scrambled datablock for reception by the at least one TUE.
 2. The method of claim 1wherein the group ID is a function of one or more of: UE cooperation(UC) group ID, TUE sub-group ID, TUE PHY identity, TUE medium accesscontrol (MAC) ID, TUE higher-layer ID, CUE sub-group ID, CUE PHYidentity, CUE MAC ID, CUE higher-layer ID, cell ID.
 3. The method ofclaim 2, wherein one or more of the following parameters is (or are)predefined, semi-statically configured by higher layer signaling, ordynamically configured by PHY layer signaling: UE cooperation (UC) groupID, TUE sub-group ID, TUE PHY identity, TUE medium access control (MAC)ID, TUE higher-layer ID, CUE sub-group ID, CUE PHY identity, CUE MAC ID,CUE higher-layer ID, cell ID.
 4. The method of claim 1, wherein thetransmitting is a unicast transmission to one TUE, wherein the one TUEis indicated or identified by a TUE sub-group ID or a combination of aUE cooperation (UC) group ID and the TUE sub-group ID.
 5. The method ofclaim 1, wherein the transmitting is a unicast transmission to one TUE,wherein the one TUE is indicated or identified by a DMRS sequence. 6.The method of claim 5, wherein the DMRS sequence is generated based onat least a group ID associated with the unicast transmission.
 7. Themethod of claim 1, wherein the scrambling is also based on a group baseddata scrambling ID.
 8. The method of claim 7, wherein the group basedscrambling ID is: based on a configuration of the group based datascrambling ID received via higher layer signalling; or based on a cellID.
 9. The method of claim 1 further comprising: for unicasttransmission to a single TUE, the group ID comprises a UE cooperationgroup ID (UC group ID) common to all members of the UC group combinedwith a single TUE sub-group ID; or for multicast transmission to a groupof TUEs, the group ID comprises a UE cooperation group ID (UC group ID)common to all members of the UC group.
 10. The method of claim 1 furthercomprising: receiving signaling to configure the CUE to assist the atleast one TUE.
 11. The method of claim 1, further comprising:transmitting sidelink control information (SCI) signaling indicatingtransmission resources and parameters for use by the at least one TUE indetecting and decoding second modulated scrambled data block.
 12. Themethod of claim 11 wherein transmitting SCI signaling is performed usinga group-cast transmission to one or more UEs in a group of UEsidentified by the group ID or a unicast transmission to one TUE.
 13. Themethod of claim 11, wherein transmitting sidelink control information(SCI) signaling further comprises scrambling a CRC of a set of sidelinkcontrol information (SCI) information bits based on at least the groupID, the SCI information bits and the scrambled CRC together forming anSCI coded block; scrambling the SCI coded block based on at least thegroup ID to produce a scrambled SCI coded block; modulating thescrambled SCI coded block to produce a modulated SCI coded block;transmitting the modulated SCI coded block for reception by the at leastone TUE; wherein the group ID is known by the CUE and the at least onetarget UE (TUE).
 14. The method of claim 13 wherein the scrambling theSCI is also based on a group based control scrambling ID.
 15. The methodof claim 14 wherein the group based control scrambling ID is based on aconfiguration of the group based control scrambling ID received viahigher layer signaling.
 16. The method of claim 1 further comprising theUE assisting at least one source UE (SUE), by receiving traffic from theat least one SUE and forwarding the traffic to the base station oranother UE.
 17. The method of claim 1 wherein determining that thedecoded data block is for said at least one TUE comprises attempting todescramble the scrambled data block with a scrambling sequence specificto the CUE, and also with the scrambling sequence based on the group ID.18. The method of claim 1 wherein the first modulated scrambled datablock is scrambled with a different scrambling sequence than the secondmodulated scrambled data block.
 19. The method of claim 1 wherein thefirst modulated scrambled data block is modulated with a differentmodulation and coding scheme than the second modulated scrambled datablock.
 20. The method of claim 1 further comprising: the CUE receiving afirst demodulation reference symbol (DMRS) from the base station; theCUE determining that the first DMRS is associated with the firstmodulated scrambled data block transmitted by the base station forreception by the at least one target UE; the CUE generating a DMRS basedon at least the group ID; modulating the DMRS to produce a modulatedDMRS; transmitting the modulated DMRS for reception by at least onetarget UE; wherein the group ID is known by the UE and the at least onetarget UE (TUE).
 21. The method of claim 1 wherein the UE is one of agroup of more than one CUE in a UE group that are assisting the at leastone target UE (TUE), wherein the UE group is associated with the groupID.
 22. A user equipment (UE) comprising at least a processor andmemory, the UE configured to perform the method of claim 1.